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Linux/drivers/rtc/rtc-ds1511.c

  1 /*
  2  * An rtc driver for the Dallas DS1511
  3  *
  4  * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
  5  * Copyright (C) 2007 Andrew Sharp <andy.sharp@lsi.com>
  6  *
  7  * This program is free software; you can redistribute it and/or modify
  8  * it under the terms of the GNU General Public License version 2 as
  9  * published by the Free Software Foundation.
 10  *
 11  * Real time clock driver for the Dallas 1511 chip, which also
 12  * contains a watchdog timer.  There is a tiny amount of code that
 13  * platform code could use to mess with the watchdog device a little
 14  * bit, but not a full watchdog driver.
 15  */
 16 
 17 #include <linux/bcd.h>
 18 #include <linux/init.h>
 19 #include <linux/kernel.h>
 20 #include <linux/gfp.h>
 21 #include <linux/delay.h>
 22 #include <linux/interrupt.h>
 23 #include <linux/rtc.h>
 24 #include <linux/platform_device.h>
 25 #include <linux/io.h>
 26 #include <linux/module.h>
 27 
 28 #define DRV_VERSION "0.6"
 29 
 30 enum ds1511reg {
 31         DS1511_SEC = 0x0,
 32         DS1511_MIN = 0x1,
 33         DS1511_HOUR = 0x2,
 34         DS1511_DOW = 0x3,
 35         DS1511_DOM = 0x4,
 36         DS1511_MONTH = 0x5,
 37         DS1511_YEAR = 0x6,
 38         DS1511_CENTURY = 0x7,
 39         DS1511_AM1_SEC = 0x8,
 40         DS1511_AM2_MIN = 0x9,
 41         DS1511_AM3_HOUR = 0xa,
 42         DS1511_AM4_DATE = 0xb,
 43         DS1511_WD_MSEC = 0xc,
 44         DS1511_WD_SEC = 0xd,
 45         DS1511_CONTROL_A = 0xe,
 46         DS1511_CONTROL_B = 0xf,
 47         DS1511_RAMADDR_LSB = 0x10,
 48         DS1511_RAMDATA = 0x13
 49 };
 50 
 51 #define DS1511_BLF1     0x80
 52 #define DS1511_BLF2     0x40
 53 #define DS1511_PRS      0x20
 54 #define DS1511_PAB      0x10
 55 #define DS1511_TDF      0x08
 56 #define DS1511_KSF      0x04
 57 #define DS1511_WDF      0x02
 58 #define DS1511_IRQF     0x01
 59 #define DS1511_TE       0x80
 60 #define DS1511_CS       0x40
 61 #define DS1511_BME      0x20
 62 #define DS1511_TPE      0x10
 63 #define DS1511_TIE      0x08
 64 #define DS1511_KIE      0x04
 65 #define DS1511_WDE      0x02
 66 #define DS1511_WDS      0x01
 67 #define DS1511_RAM_MAX  0xff
 68 
 69 #define RTC_CMD         DS1511_CONTROL_B
 70 #define RTC_CMD1        DS1511_CONTROL_A
 71 
 72 #define RTC_ALARM_SEC   DS1511_AM1_SEC
 73 #define RTC_ALARM_MIN   DS1511_AM2_MIN
 74 #define RTC_ALARM_HOUR  DS1511_AM3_HOUR
 75 #define RTC_ALARM_DATE  DS1511_AM4_DATE
 76 
 77 #define RTC_SEC         DS1511_SEC
 78 #define RTC_MIN         DS1511_MIN
 79 #define RTC_HOUR        DS1511_HOUR
 80 #define RTC_DOW         DS1511_DOW
 81 #define RTC_DOM         DS1511_DOM
 82 #define RTC_MON         DS1511_MONTH
 83 #define RTC_YEAR        DS1511_YEAR
 84 #define RTC_CENTURY     DS1511_CENTURY
 85 
 86 #define RTC_TIE DS1511_TIE
 87 #define RTC_TE  DS1511_TE
 88 
 89 struct rtc_plat_data {
 90         struct rtc_device *rtc;
 91         void __iomem *ioaddr;           /* virtual base address */
 92         int irq;
 93         unsigned int irqen;
 94         int alrm_sec;
 95         int alrm_min;
 96         int alrm_hour;
 97         int alrm_mday;
 98         spinlock_t lock;
 99 };
100 
101 static DEFINE_SPINLOCK(ds1511_lock);
102 
103 static __iomem char *ds1511_base;
104 static u32 reg_spacing = 1;
105 
106 static noinline void
107 rtc_write(uint8_t val, uint32_t reg)
108 {
109         writeb(val, ds1511_base + (reg * reg_spacing));
110 }
111 
112 static inline void
113 rtc_write_alarm(uint8_t val, enum ds1511reg reg)
114 {
115         rtc_write((val | 0x80), reg);
116 }
117 
118 static noinline uint8_t
119 rtc_read(enum ds1511reg reg)
120 {
121         return readb(ds1511_base + (reg * reg_spacing));
122 }
123 
124 static inline void
125 rtc_disable_update(void)
126 {
127         rtc_write((rtc_read(RTC_CMD) & ~RTC_TE), RTC_CMD);
128 }
129 
130 static void
131 rtc_enable_update(void)
132 {
133         rtc_write((rtc_read(RTC_CMD) | RTC_TE), RTC_CMD);
134 }
135 
136 /*
137  * #define DS1511_WDOG_RESET_SUPPORT
138  *
139  * Uncomment this if you want to use these routines in
140  * some platform code.
141  */
142 #ifdef DS1511_WDOG_RESET_SUPPORT
143 /*
144  * just enough code to set the watchdog timer so that it
145  * will reboot the system
146  */
147 void
148 ds1511_wdog_set(unsigned long deciseconds)
149 {
150         /*
151          * the wdog timer can take 99.99 seconds
152          */
153         deciseconds %= 10000;
154         /*
155          * set the wdog values in the wdog registers
156          */
157         rtc_write(bin2bcd(deciseconds % 100), DS1511_WD_MSEC);
158         rtc_write(bin2bcd(deciseconds / 100), DS1511_WD_SEC);
159         /*
160          * set wdog enable and wdog 'steering' bit to issue a reset
161          */
162         rtc_write(DS1511_WDE | DS1511_WDS, RTC_CMD);
163 }
164 
165 void
166 ds1511_wdog_disable(void)
167 {
168         /*
169          * clear wdog enable and wdog 'steering' bits
170          */
171         rtc_write(rtc_read(RTC_CMD) & ~(DS1511_WDE | DS1511_WDS), RTC_CMD);
172         /*
173          * clear the wdog counter
174          */
175         rtc_write(0, DS1511_WD_MSEC);
176         rtc_write(0, DS1511_WD_SEC);
177 }
178 #endif
179 
180 /*
181  * set the rtc chip's idea of the time.
182  * stupidly, some callers call with year unmolested;
183  * and some call with  year = year - 1900.  thanks.
184  */
185 static int ds1511_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
186 {
187         u8 mon, day, dow, hrs, min, sec, yrs, cen;
188         unsigned long flags;
189 
190         /*
191          * won't have to change this for a while
192          */
193         if (rtc_tm->tm_year < 1900)
194                 rtc_tm->tm_year += 1900;
195 
196         if (rtc_tm->tm_year < 1970)
197                 return -EINVAL;
198 
199         yrs = rtc_tm->tm_year % 100;
200         cen = rtc_tm->tm_year / 100;
201         mon = rtc_tm->tm_mon + 1;   /* tm_mon starts at zero */
202         day = rtc_tm->tm_mday;
203         dow = rtc_tm->tm_wday & 0x7; /* automatic BCD */
204         hrs = rtc_tm->tm_hour;
205         min = rtc_tm->tm_min;
206         sec = rtc_tm->tm_sec;
207 
208         if ((mon > 12) || (day == 0))
209                 return -EINVAL;
210 
211         if (day > rtc_month_days(rtc_tm->tm_mon, rtc_tm->tm_year))
212                 return -EINVAL;
213 
214         if ((hrs >= 24) || (min >= 60) || (sec >= 60))
215                 return -EINVAL;
216 
217         /*
218          * each register is a different number of valid bits
219          */
220         sec = bin2bcd(sec) & 0x7f;
221         min = bin2bcd(min) & 0x7f;
222         hrs = bin2bcd(hrs) & 0x3f;
223         day = bin2bcd(day) & 0x3f;
224         mon = bin2bcd(mon) & 0x1f;
225         yrs = bin2bcd(yrs) & 0xff;
226         cen = bin2bcd(cen) & 0xff;
227 
228         spin_lock_irqsave(&ds1511_lock, flags);
229         rtc_disable_update();
230         rtc_write(cen, RTC_CENTURY);
231         rtc_write(yrs, RTC_YEAR);
232         rtc_write((rtc_read(RTC_MON) & 0xe0) | mon, RTC_MON);
233         rtc_write(day, RTC_DOM);
234         rtc_write(hrs, RTC_HOUR);
235         rtc_write(min, RTC_MIN);
236         rtc_write(sec, RTC_SEC);
237         rtc_write(dow, RTC_DOW);
238         rtc_enable_update();
239         spin_unlock_irqrestore(&ds1511_lock, flags);
240 
241         return 0;
242 }
243 
244 static int ds1511_rtc_read_time(struct device *dev, struct rtc_time *rtc_tm)
245 {
246         unsigned int century;
247         unsigned long flags;
248 
249         spin_lock_irqsave(&ds1511_lock, flags);
250         rtc_disable_update();
251 
252         rtc_tm->tm_sec = rtc_read(RTC_SEC) & 0x7f;
253         rtc_tm->tm_min = rtc_read(RTC_MIN) & 0x7f;
254         rtc_tm->tm_hour = rtc_read(RTC_HOUR) & 0x3f;
255         rtc_tm->tm_mday = rtc_read(RTC_DOM) & 0x3f;
256         rtc_tm->tm_wday = rtc_read(RTC_DOW) & 0x7;
257         rtc_tm->tm_mon = rtc_read(RTC_MON) & 0x1f;
258         rtc_tm->tm_year = rtc_read(RTC_YEAR) & 0x7f;
259         century = rtc_read(RTC_CENTURY);
260 
261         rtc_enable_update();
262         spin_unlock_irqrestore(&ds1511_lock, flags);
263 
264         rtc_tm->tm_sec = bcd2bin(rtc_tm->tm_sec);
265         rtc_tm->tm_min = bcd2bin(rtc_tm->tm_min);
266         rtc_tm->tm_hour = bcd2bin(rtc_tm->tm_hour);
267         rtc_tm->tm_mday = bcd2bin(rtc_tm->tm_mday);
268         rtc_tm->tm_wday = bcd2bin(rtc_tm->tm_wday);
269         rtc_tm->tm_mon = bcd2bin(rtc_tm->tm_mon);
270         rtc_tm->tm_year = bcd2bin(rtc_tm->tm_year);
271         century = bcd2bin(century) * 100;
272 
273         /*
274          * Account for differences between how the RTC uses the values
275          * and how they are defined in a struct rtc_time;
276          */
277         century += rtc_tm->tm_year;
278         rtc_tm->tm_year = century - 1900;
279 
280         rtc_tm->tm_mon--;
281 
282         if (rtc_valid_tm(rtc_tm) < 0) {
283                 dev_err(dev, "retrieved date/time is not valid.\n");
284                 rtc_time_to_tm(0, rtc_tm);
285         }
286         return 0;
287 }
288 
289 /*
290  * write the alarm register settings
291  *
292  * we only have the use to interrupt every second, otherwise
293  * known as the update interrupt, or the interrupt if the whole
294  * date/hours/mins/secs matches.  the ds1511 has many more
295  * permutations, but the kernel doesn't.
296  */
297 static void
298 ds1511_rtc_update_alarm(struct rtc_plat_data *pdata)
299 {
300         unsigned long flags;
301 
302         spin_lock_irqsave(&pdata->lock, flags);
303         rtc_write(pdata->alrm_mday < 0 || (pdata->irqen & RTC_UF) ?
304                0x80 : bin2bcd(pdata->alrm_mday) & 0x3f,
305                RTC_ALARM_DATE);
306         rtc_write(pdata->alrm_hour < 0 || (pdata->irqen & RTC_UF) ?
307                0x80 : bin2bcd(pdata->alrm_hour) & 0x3f,
308                RTC_ALARM_HOUR);
309         rtc_write(pdata->alrm_min < 0 || (pdata->irqen & RTC_UF) ?
310                0x80 : bin2bcd(pdata->alrm_min) & 0x7f,
311                RTC_ALARM_MIN);
312         rtc_write(pdata->alrm_sec < 0 || (pdata->irqen & RTC_UF) ?
313                0x80 : bin2bcd(pdata->alrm_sec) & 0x7f,
314                RTC_ALARM_SEC);
315         rtc_write(rtc_read(RTC_CMD) | (pdata->irqen ? RTC_TIE : 0), RTC_CMD);
316         rtc_read(RTC_CMD1);     /* clear interrupts */
317         spin_unlock_irqrestore(&pdata->lock, flags);
318 }
319 
320 static int
321 ds1511_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
322 {
323         struct platform_device *pdev = to_platform_device(dev);
324         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
325 
326         if (pdata->irq <= 0)
327                 return -EINVAL;
328 
329         pdata->alrm_mday = alrm->time.tm_mday;
330         pdata->alrm_hour = alrm->time.tm_hour;
331         pdata->alrm_min = alrm->time.tm_min;
332         pdata->alrm_sec = alrm->time.tm_sec;
333         if (alrm->enabled)
334                 pdata->irqen |= RTC_AF;
335 
336         ds1511_rtc_update_alarm(pdata);
337         return 0;
338 }
339 
340 static int
341 ds1511_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
342 {
343         struct platform_device *pdev = to_platform_device(dev);
344         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
345 
346         if (pdata->irq <= 0)
347                 return -EINVAL;
348 
349         alrm->time.tm_mday = pdata->alrm_mday < 0 ? 0 : pdata->alrm_mday;
350         alrm->time.tm_hour = pdata->alrm_hour < 0 ? 0 : pdata->alrm_hour;
351         alrm->time.tm_min = pdata->alrm_min < 0 ? 0 : pdata->alrm_min;
352         alrm->time.tm_sec = pdata->alrm_sec < 0 ? 0 : pdata->alrm_sec;
353         alrm->enabled = (pdata->irqen & RTC_AF) ? 1 : 0;
354         return 0;
355 }
356 
357 static irqreturn_t
358 ds1511_interrupt(int irq, void *dev_id)
359 {
360         struct platform_device *pdev = dev_id;
361         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
362         unsigned long events = 0;
363 
364         spin_lock(&pdata->lock);
365         /*
366          * read and clear interrupt
367          */
368         if (rtc_read(RTC_CMD1) & DS1511_IRQF) {
369                 events = RTC_IRQF;
370                 if (rtc_read(RTC_ALARM_SEC) & 0x80)
371                         events |= RTC_UF;
372                 else
373                         events |= RTC_AF;
374                 rtc_update_irq(pdata->rtc, 1, events);
375         }
376         spin_unlock(&pdata->lock);
377         return events ? IRQ_HANDLED : IRQ_NONE;
378 }
379 
380 static int ds1511_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
381 {
382         struct platform_device *pdev = to_platform_device(dev);
383         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
384 
385         if (pdata->irq <= 0)
386                 return -EINVAL;
387         if (enabled)
388                 pdata->irqen |= RTC_AF;
389         else
390                 pdata->irqen &= ~RTC_AF;
391         ds1511_rtc_update_alarm(pdata);
392         return 0;
393 }
394 
395 static const struct rtc_class_ops ds1511_rtc_ops = {
396         .read_time              = ds1511_rtc_read_time,
397         .set_time               = ds1511_rtc_set_time,
398         .read_alarm             = ds1511_rtc_read_alarm,
399         .set_alarm              = ds1511_rtc_set_alarm,
400         .alarm_irq_enable       = ds1511_rtc_alarm_irq_enable,
401 };
402 
403 static ssize_t
404 ds1511_nvram_read(struct file *filp, struct kobject *kobj,
405                   struct bin_attribute *ba,
406                   char *buf, loff_t pos, size_t size)
407 {
408         ssize_t count;
409 
410         /*
411          * if count is more than one, turn on "burst" mode
412          * turn it off when you're done
413          */
414         if (size > 1)
415                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
416 
417         if (pos > DS1511_RAM_MAX)
418                 pos = DS1511_RAM_MAX;
419 
420         if (size + pos > DS1511_RAM_MAX + 1)
421                 size = DS1511_RAM_MAX - pos + 1;
422 
423         rtc_write(pos, DS1511_RAMADDR_LSB);
424         for (count = 0; size > 0; count++, size--)
425                 *buf++ = rtc_read(DS1511_RAMDATA);
426 
427         if (count > 1)
428                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
429 
430         return count;
431 }
432 
433 static ssize_t
434 ds1511_nvram_write(struct file *filp, struct kobject *kobj,
435                    struct bin_attribute *bin_attr,
436                    char *buf, loff_t pos, size_t size)
437 {
438         ssize_t count;
439 
440         /*
441          * if count is more than one, turn on "burst" mode
442          * turn it off when you're done
443          */
444         if (size > 1)
445                 rtc_write((rtc_read(RTC_CMD) | DS1511_BME), RTC_CMD);
446 
447         if (pos > DS1511_RAM_MAX)
448                 pos = DS1511_RAM_MAX;
449 
450         if (size + pos > DS1511_RAM_MAX + 1)
451                 size = DS1511_RAM_MAX - pos + 1;
452 
453         rtc_write(pos, DS1511_RAMADDR_LSB);
454         for (count = 0; size > 0; count++, size--)
455                 rtc_write(*buf++, DS1511_RAMDATA);
456 
457         if (count > 1)
458                 rtc_write((rtc_read(RTC_CMD) & ~DS1511_BME), RTC_CMD);
459 
460         return count;
461 }
462 
463 static struct bin_attribute ds1511_nvram_attr = {
464         .attr = {
465                 .name = "nvram",
466                 .mode = S_IRUGO | S_IWUSR,
467         },
468         .size = DS1511_RAM_MAX,
469         .read = ds1511_nvram_read,
470         .write = ds1511_nvram_write,
471 };
472 
473 static int ds1511_rtc_probe(struct platform_device *pdev)
474 {
475         struct resource *res;
476         struct rtc_plat_data *pdata;
477         int ret = 0;
478 
479         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
480         if (!pdata)
481                 return -ENOMEM;
482 
483         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
484         ds1511_base = devm_ioremap_resource(&pdev->dev, res);
485         if (IS_ERR(ds1511_base))
486                 return PTR_ERR(ds1511_base);
487         pdata->ioaddr = ds1511_base;
488         pdata->irq = platform_get_irq(pdev, 0);
489 
490         /*
491          * turn on the clock and the crystal, etc.
492          */
493         rtc_write(0, RTC_CMD);
494         rtc_write(0, RTC_CMD1);
495         /*
496          * clear the wdog counter
497          */
498         rtc_write(0, DS1511_WD_MSEC);
499         rtc_write(0, DS1511_WD_SEC);
500         /*
501          * start the clock
502          */
503         rtc_enable_update();
504 
505         /*
506          * check for a dying bat-tree
507          */
508         if (rtc_read(RTC_CMD1) & DS1511_BLF1)
509                 dev_warn(&pdev->dev, "voltage-low detected.\n");
510 
511         spin_lock_init(&pdata->lock);
512         platform_set_drvdata(pdev, pdata);
513 
514         pdata->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
515                                               &ds1511_rtc_ops, THIS_MODULE);
516         if (IS_ERR(pdata->rtc))
517                 return PTR_ERR(pdata->rtc);
518 
519         /*
520          * if the platform has an interrupt in mind for this device,
521          * then by all means, set it
522          */
523         if (pdata->irq > 0) {
524                 rtc_read(RTC_CMD1);
525                 if (devm_request_irq(&pdev->dev, pdata->irq, ds1511_interrupt,
526                         IRQF_SHARED, pdev->name, pdev) < 0) {
527 
528                         dev_warn(&pdev->dev, "interrupt not available.\n");
529                         pdata->irq = 0;
530                 }
531         }
532 
533         ret = sysfs_create_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
534         if (ret)
535                 dev_err(&pdev->dev, "Unable to create sysfs entry: %s\n",
536                         ds1511_nvram_attr.attr.name);
537 
538         return 0;
539 }
540 
541 static int ds1511_rtc_remove(struct platform_device *pdev)
542 {
543         struct rtc_plat_data *pdata = platform_get_drvdata(pdev);
544 
545         sysfs_remove_bin_file(&pdev->dev.kobj, &ds1511_nvram_attr);
546         if (pdata->irq > 0) {
547                 /*
548                  * disable the alarm interrupt
549                  */
550                 rtc_write(rtc_read(RTC_CMD) & ~RTC_TIE, RTC_CMD);
551                 rtc_read(RTC_CMD1);
552         }
553         return 0;
554 }
555 
556 /* work with hotplug and coldplug */
557 MODULE_ALIAS("platform:ds1511");
558 
559 static struct platform_driver ds1511_rtc_driver = {
560         .probe          = ds1511_rtc_probe,
561         .remove         = ds1511_rtc_remove,
562         .driver         = {
563                 .name   = "ds1511",
564                 .owner  = THIS_MODULE,
565         },
566 };
567 
568 module_platform_driver(ds1511_rtc_driver);
569 
570 MODULE_AUTHOR("Andrew Sharp <andy.sharp@lsi.com>");
571 MODULE_DESCRIPTION("Dallas DS1511 RTC driver");
572 MODULE_LICENSE("GPL");
573 MODULE_VERSION(DRV_VERSION);
574 

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